1. Field of the Disclosure
The present disclosure relates generally to a media feed system of an image forming device, and, in particular, to a pick roll of a pick mechanism of the media feed system.
2. Description of the Related Art
In prior art media feed assemblies, a pick mechanism is used in combination with a downstream aligner for feeding sheets of media into an image forming device. The aligner ensures that the media being fed by the pick mechanism, such as a pick roll, has no misalignment, such as paper skew, upon reaching, contacting or passing through a downstream feed roll pair. In general, while the pick mechanism feeds media in a media feed direction along a media path thereof, a leading edge of fed media is aligned by contact with the aligner positioned transverse a media feed direction. The pick mechanism continues to feed the media to the downstream feed roll pair. The pick mechanism may use a D-roll as is known in the art to feed a media sheet into the downstream aligner. The D-roll has a pick tire having a given tread width and a flat portion when the D-roll is no longer in contact with the media sheet being feed. The flat portion allows a downstream feed roll pair to feed the media sheet with no feeding force being applied by the D-roll of the pick mechanism that may skew the media sheet.
When feeding the media sheet, the D-roll rotates and moves the media sheet in the media feed direction toward the aligner. A bubble forms in a portion of the media sheet contacting the aligner and the leading edge aligns with the aligner. In this manner, each media sheet is fed along the media feed path with proper alignment. During bubble formation and leading edge alignment, the media sheet is still being fed by the pick roll which is designed to provide sufficient force to move the largest width of media useable in the image forming device. That same force is also applied to the narrower media types. Because of this, the skew of wide media is more readily corrected than that of narrow media. In particular, a longer moment arm is created when the leading edge of the wide media contacts the aligner and provides sufficient torque to allow the media to slip relative to the pick roll and pick tire. Whereas with narrow media a smaller moment arm is created when the leading edge contacts the aligner and provides less torque to overcome the force supplied by the pick roll and pick tire, and, as a result, skewing may not be completely corrected. Also a less stiff bubble is formed with the wide media as compared to a stiffer bubble formed in narrower media. It would be desirable to have a pick mechanism and pick roll in combination with an aligner that could correct skew in both wide and narrow media.